Large capacity oil fuse



Dec. 27, 1932. P, E H 1,892,102

LARGE CAPACITY OIL FUSE Filed June'l9, 1931 Inventor. Percy Ejla 'tl k'cj Patented Dec. 27, 1932 UNITED STATES PATENT, o F c 1 PERCY E. HART, DECEASED, LATE OF TORONTO, ONTARIO, CANADA, BY ETHEL EAGEN HART, EXECUTRIX, TORONTO, CANADA i I LARGE CAPACITY OIL FUSE I Application filed June 19,

The principal objects of the invention are, to effect a material saving in the cost of the protective devices in plants handling very large electrical currents, and to provide an oil fuse capable of rupturing very large currents under high voltage conditions without injury to the fuse container and in a safe and rellable manner.

The principal features of the invention 1 consists in the arrangement of an indicator connected with the shutter to show when the fuse has been blown. I

In the drawing, Figure 1 is a vertical midsectional view taken transversely of the central partition between the electrical terminals.

Figure 2-is a vertical section through the line 22 of Figure 1.

Ifigure ,3 is a plan vlew of the top of the casing.

In the construction of the device herein shown, a steel tank 1, preferably of cylindrical form and having a dished bottom, is closed with a cover 2 which is provided with a pair of orifices 3. s

Angle flanged supports 4 are secured .to the cover in alignment with said orifices and support the terminals 5 and 6. I

A flange 7' extends downwardly from the underside of the cover 2 between the orifices 3 and to this flange is rigidly secured a heavy insulating plate 8 which forms an insulating barrier between the two terminals and a horizontal baffle 9 is secured to the bottom edge of this plate. s I

The plate 8 and bafile9 do not extend the full width of the tank 1 and the oil flows uni formly around the barrier. A I A An aperturelO is formed centrally of the width of the barrier 8 adjacent to the lower end through which the fuse wires 11 extendingbetweenthe terminals 5 and 6 extend.

1931. Serial No. 545,513.

A pair of plates 12 each formed with lonif gitudinal slots 13 are mountedone on each side of the plate 8 and are connected at the top by a cross plate 1 1 extending through a slot 15 in the plate 8. I

A coil compression spring 16 is arranged within the slot 15 and bears downwardly against the plate 14 connecting the plates 12 and holds the plates 12 in'a pressure contact with the fuse wires passing through the barrier, so that upon the fusing of the fuse wires the spring pressure forces the plates 12 downwardly to close the aperture 10, thereby quenching the are which is liable otherwise to be established between the, severed ends of the fuse.

The melting of the fuse wires under severe overloads or short circuit conditions establishes an arc and the oil contained in the tank 1 has a distinctly beneficial effect in extinguishing the arc. The oil also has the efiect of raising therupture capacity of the use.

The resulting condition is amplified by the interposition of the barrier 8 with a hori zontal baflie 9.

Electro-mechanical forces present with large currents tend to draw the arc stream resulting from the melting fusein a direction such that. as large an area as possible will be enclosed by the current loop.

With the present device the structure tends to throw the arodownwardly but since the barrier 8 is interposed in the arm'stream it will be forcibly broken into two sections and so will be rapidly extinguished.

This action is rendered practically instantaneous by the spring operated shutter formed by the plates '12.

It is found with a structure such as described very little volatilization of oil takes place, but any pressure that is created isreleased through the escape device 17 arranged ontop of the tank. This may be of any suitable form. I

It is extremely desirable that some indication should be given of-the rupture of a fuse and because of the mechanical movement of the plates 12 a very simple indication means be provided. As herein shown a rod 18 is -able means mounted on each secured to one of the plates 12 and extends upwardly through the opening in the cover 2 into an enclosed gauge casing 19. This is here shown in the form of a metal tube 20 at the outer end and enclosing a glass tube 21 sealed at both ends.

The metal tube 19 is provided with openings 22 and 23 through which a target 21 secured to the rod 18 is visible.

An insulating lining 25 of suitable dielectric material lines the inner side of the tank 1. It may be found desirable on small installations to form the tank 1 entirely of insulating material.

\Vhen the fuse wires are in contact the target shows in the upper opening, but when they have been fused and 'the barrier is closed, the intimation appears in the lower opening.

It will be readily understood that means may be provided for operating some simple form of electrical contact means through the operation of the target member to ive an aufdible signal in the event of the brealring of a use.

A device such as described is extremely desirable and will in certain forms of installations be capable of use in place of the much more expensive and elaborate circuit breaker devices in the form of switch members which are at present used.

What is claimed is:

' 1. In a large capacity oil fuse the combination of spaced electric-terminals, an insulating partition interposed between said terminals, said partition having an opening therethrough, fusible conductors extending through said partition opening and connected with said terminals, displaceside of said partition for closing said partition openings against pressure from either side on the rupture of said fusible conductors, and means co-operating with both of said displaceable means for effecting the positive and simultanenous displacement thereof.

2. In a large capacity oil fuse the combination of spaced electric terminals, an insulating partition interposed between said terminals, said partition having an opening therethrough, fusible conductors extending through said partition opening and connected with said terminals, a pair of shutters mounted one on each side of said partition for movement parallel thereto adapted to close ti I over said opening at each side of the partition on the rupture of said fusible conductors, guide means engaging said shutters to hold same in close surface relation to the surface of said partition, and means for positively and simultanenously actuating said pair of shutters.

3. In a large capacity oil fuse, the combination of spaced electric terminals, an insulatin partition interposed between said termina s, said partition having an opening therethrough, fusible conductors extendm through said partition opening and connecte with said terminals, insulating closure lates movably mounted one on each side 0 said insulating partition and normally resting on said fusible conductors, means operatively connecting said closure plates to form a single operable unit, and spring means engaging said operative plate connecting means to si multaneously move said insulating plates to double close said partition opening on the rupture of said fusible elements.

I 1. In a large capacity oil fuse, the combination of spaced terminals extending downwardly, a vertical insulating partition mounted in said tank and forming a barrier between said terminals, said partition having an opening therethrough spaced above the bottom thereof, fusible conductors connecting said terminals and extending through said opening, means for double sealing said opening on the rupture of said fusible conductors, and an insulating bafile means extending transversely of said insulating partition below said fusible conductors and opening and forming a direct lateral continuation of said vertical artition to obstruct the downward travel 0 the are on the fusing of said fusible conductors.

5. In a large capacity oil fuse, the combination of spaced electric terminals, an insulating partition interposed between said terminals, saidpartition havingan opening therethrough, fusible conductors extending through said partition opening and connected with said terminals, insulating plates arranged one in surface contact with each side of said partition and having aligned slots, guide bolts extending through said partition and through said ali ed plate slots and guiding said plates an acting as stops to limit the movement thereof, said plates normally resting on said fusible conductors, and spring means for simultaneously forcing said plates down to double close said partition opening on the rupture of said fusible conductors.

6. In a large capacity oil fuse, the combination of spaced electric terminals, an insulating partition interposed between said terminals, said partition having an opening therethrough, fusible conductors extending through said partition opening and connected with said terminals, a pair of insulating plates arranged one in surface contact'with each side of said partition and havin aligned slots, guide bolts extending througfi said partition and throu h said slots and guiding said plates, said olts holdin said plates in close sliding contact with t e respective sides of said partition, said plates normally resting on said fusible conductors, said partition having a slot therein extending-above the upper end of said lates, a connecting bridge piece extending etween said iSo plates and through said latter slot, and a compression spring arranged in said partition slot and exerting a downward pressure on said connecting bridge piece to simultaneously close both of said plates over said partition opening on the rupture of said fusible conductors.

7. In a large capacity oilfuse, the combination with a pair of terminals spaced apart and having an insulating partition suspended therebetween and extending therebelow, of an insulating baflie member secured to and supported by said insulating partition and extending transversely thereof at the bottom, and forming a direct continuation of said partition and extending beyond said terminals, said partition having an opening therethrough above said bafile, fusible conductors extending through said opening and connecting said terminals, and means for closing said opening in the plate above said transverse baflie on the rupture of said fusible elements whereby an extended circuitous route is established for the ensuing arc between the terminals.

8. In a large capacity oil fuse, the combi- I nation with electric terminals having are interrupting means interposed therebetween including a movable closure member, fusible conductors connecting the terminals and normally holding said closure means 1n open position, of a rod extending from said closure means and actuated by movement of said closure member, said rod having a target disc mounted thereon, and an oil proof enclosure for said target disc having a transparent window for rendering the target disc visible when said closure means has moved to its closed position.

ETHEL 'EAGEN HART,

Ewecutriw of Percy E. Hart, Deceased. 

